Character matrices for phototypesetters

ABSTRACT

A character matrix array for a flying spot photographic character scanner is formed as a rigid plate of steel or the like with windows therein and a resilient gasket holds one or more arrays of character matrices on stable base films across the windows. The piece or pieces of film are prepunched with registration slots that fit registration pins in the frame.

United States Patent 1191 Purdy et al. May 28, 1974 CHARACTER MATRICES FOR 2,585,188 2/1952 Taylor 95/45 PHQTOTYPESETTERS 2,585,188 2/1952 Taylor 1 95/4.5 2,701,991 2/1955 Croucher... 95/45 Inventors: Haydn y, Down Cottage 3,074,181 l/l963 Watson 95/85 x Down PL, Windsor; Ronald C.

McIntosh Avenue Primary Examiner-John M. Horan Albans both of England Attorney, Agent, or Fir mBiebel, French & Bugg [22] Filed: Aug. 10, 1970 [211 App]. No.: 62,531 S RACT A character matrix array for a flying spot photo- 52 us. c1. 354/292, 95/45 graphic character Scanner iS formed as a rigid plate of 51 1111. c1. G03b 15/00 Smell the like with windows therein and a resilient [58] Field of Search 95/4.5, 85 gasket holds one more arrays of character matrices on stable base films across the windows. The piece or 5 References Cited pieces of film are prepunched with registration slots UNITED STATES PATENTS that fit registration pins in the frame. 2,231,899 3 Claims, 2 Drawing Figures 2/1941 Freund 95/85 PATENTEDMY 28 1974 AQ wwvv/ g PATENTEDMAY 28 m 3.8 131683 sum 2 or 2 I W (Ix/(O 20 INVENTORS HAYDN V. PURDY 8: RONALD C. MclNTOSl-l ATTOR N E Y3 CHARACTER FOR U PHOTOTYPESETTERS BACKGROUND OF THE INVENTION This invention relates to flying spot scanner character generators for use in phototypesetters. In. such generators a. photographic glass plate is used to provide negative character images which are indexed and scanned. by cathode ray tube means in order to locate successive character images and to describe these images assuccessive vertical image sections. Such a plate, known asa grid, must be positionedv to (say) 0.001 inch in the Y direction, where electronic lock-on is critical, and somewhat less critically in the X direction, where electronic lock-on is more tolerant; further, the plate must present in the Z axis an image plane within plus or minus0.002 inch over an area of approximately 7 X 7 inches. To achieve such accuracies, specially selected glassmust be used, the edges being flat ground before emulsion coating so as to enable an accurate three point lay against ball s or cylinders. Nevertheless difficulties are experienced-due to abrasion of the ground edges, and the glass may'exhibit effects such as oystershell chipping near points of contact, hazarding accurate register. The careful handling which is necessary during the original production,and=thesedifficulties notably contribute to a high unit cost and slow deliveries. A further disadvantage of the glass grid plate is that the arrangement of characters is inalterable for any given plate, the layout of which has to be specified before manufacture (although entirely successful prediction is impossible in some fields of typesetting). This leads to unnecessary duplication of large areas of the grid, and lack of flexibility in arriving at special ad hoc arrangements without time-consuming and frequent mechanical grid changes during the filmsetting process. The need for occasional extra characters, so-called pie, makes necessary additional expensive equipment, which introduces further optical and electronic problems.

SU MMARY OF, THE INVENTION In the invention now described the fragile glass registration areas are replaced by hardened material such as steel. which may be inserted into a lightweight metal or plastics frame of similar overall dimensions to the glass grid. Apertures appropriate to groups of characters, formally disposed in isolated array on the glass grid, are provided each with its own' set of registration means, e.g. two pins.

Small pieces of stable base film, which need not be precisely cut so long as they cover the aperture and do not encounter its walls, are prepunched each with a slot and 'hole according to the separation of the aforementioned registration pins. Thick base Estar" type film is very suitable. The films, which may be called changeable plaques, may now be exposed one at a time or together in a suitable camera having similarly disposed registration pins.

It is an advantage that the smaller area of coverage required of the originating lens/camera combination affords a substantial improvement in optical quality. In

I 2 addition it is easier to maintain lateral accuracy. The emulsion of the stable film is made to seat against a flange (carrying the registration pins) which constitutes the image plane; the film is held in contact against the flange by a resilient gasket, which in turn is retained to the main frame by means of thumbscrews.

The invention also embraces a system of arranging characters in a preferred array, from various master alphabets, the special facility being that a ruled master of the correct size may be projected to equal the size of any desired master alphabet, which is readily available, so that the latter may in one stage be photographed down to the correct grid size. lndividual letters of different sizes may similarly be photographed separately at differing reductions onto a single film plaque, by successive operations, registration being made infallible by the presence of the registration pins.

In an alternative version, a single sheet of register punched stable base film large enough to cover all the group images of a normal glass grid is used in a metal frame in which the film is held flat against a plate which has'a reference face over all nonimage areas. The film is held in contact with the reference face by a large resilient gasket secured by thumbscrews. Thus a film grid exposed in the holder may be removed therefrom for processing or other treatment and replaced subsequently with exactitude. I

By these means the reference responsibility is removed from vulnerable edge surfaces of ground glass to metal surfaces capable of production by standard precision engineering methods.

The invention will be clearly understood from the followingdescription of certain embodiments shown in the accompanying drawings in which:

FIG. I shows a carrier plate for an array of separate photographic character plates, while FIG. 2 shows a carrier plate for a single large photographic character plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, a plate I of steel or other hard rigid material capable of machining to very close tolerances and provided with a handle 2, first has its three planeedges and its rear face machined to precise limits with respect to one another after which is formed an array of windows 3 which are shown square but could be of any shape, .and the location of which with respect to the machined edges is closely controlled.

The rear face of plate 1 is machined to close uniplanar limits for location in a frame the internal surface of which against which said rear face is to be positioned is also machined to close tolerances.

All the windows 3 are made; as shown at the bottom lefthand corner of the plate 1; with a rectangular bore right through the plate and a larger rectangular bore partially through the plate to form a rectangular shoulder 5. The surfaces of the shoulders 5 are machined to be parallel to the borders 4 and at a precise depth therefrom. At spaced positions on each shoulder 5 are inserted pins 6, the vertical and horizontal positions of which are closely determined.

In plate I is an array of screwed holes 7 aligned with the windows 3 to receive thumbscrews 10 for the pur-' pose described below.

Photographic character plaques 8 of stable base film, such as thick base Estar" type film, are made for insertion in the window 3. The plaques are formed with a hole 81 and a slot 82 precisely located vertically in line. The plaques need not be accurately cut but must be slightly undersize with respect to the window bore 32 so that hole and slot 81, 82 can fit over the pins 6 without having been precisely located other than with respectto each other.

These plaques will have been individually processed in a camera provided with locating pins like pins 6 and with the same relative locations. An array of characters will have been photographed on to each plaque when so located.

These plaques maintain a precise uniplanar surface to close limits, so that when a set of plaques is placed one in each window 3 with its hole and slot 81, 82 on the pins 6 and with its emulsion surface against the shoulder 5, the characters will be precisely located in the X, Y, and Z axes by the pins 6 and the shoulder 5.

To hold the plaques firmly to the shoulder 5, resilient gaskets 9 with a stiff backing are inserted in the windows 3 and held firmly against the plaques by thumbscrews 10 screwed into the holes 7 so that their heads overlap the edges of one or two plaques according to their positions.

When such a matrix is put in the locating frame of a flying spot scanner, the rear face and the edges of the plate 1 are precisely located, thus locating the plaques exactly in position in the same plane for selection and scanning of the characters.

The character array in FIG. 2 is on the same general principle as FIG. I but all the individual character matriccs are on a single sheet of thick substantially rigid stable base Estar' film. The steel plate 11 with handle 12 is again machined on its threeplane edges and its rear face, anda recess 15 is machined in the surface of plate 1] leaving a border 14. In the back of recess 15 is cut an array of windows 13 precisely located with respect to the edges of the plate 11 and two spaced pins 16 similar to pins 6, FIG. I are inserted into the surface of recess 15. t

The film 18 on which have been photographed the whole array of character matrices 183 is inserted into the recess 15 and a hole 181 and a slot (not shown) engage the pins 16 to position the film 18.

Although the small pieces of film 8 in FIG. 1 are sufficiently rigid and uniplanar for their purpose, the larger sheet 18 needs support which is provided by a back cover 19 which is constituted by a solid resilient rectangular gasket with a rigid backing which fits into the recess 15 over the film 18, the apertures 191 passing over pins 16; and firmly presses the whole film 18 against the base of the recess 15.

As before, thumbscrews 20 are screwed into holes 17 in the border 14 of plate 11 and embrace the edges of the back cover 19 to hold the cover and through it to locate the film l8 firmly in uniplanar position.

What we claim is:

l. A character matrix array for a flying spot photographic character scanner having a thin film member on which master characters are formed and positioning means formed on said film member, comprising:

a rigid base plate having windows formed therethrough,

a peripheral shoulder formed on said plate surrounding the windows,

said base plate also having locating means engaging with said positioning means to locate the film over said windows,

said film member being a continuous piece fitting within said shoulder and having character arrays aligned with each of said windows,

a resilient gasket member having a stiff backing and having window openings corresponding to and co incident with said windows in said base plate, and

means for compressing said gasket means against said film member to retain said film member in a planar condition against said base plate.

2. A character matrix array for a flying spot photographic character scanner having a plurality of separate thin film members on each of which at least one array of master characters is formed and positioning means formed on each said film member, comprising a rigid base plate having one window formed therethrough for each array, each film member fitting one each within each of said windows and having dimensions smaller than said windows,

separate shoulder means formed around each of said windows,

said base plate also having locating means engaging with said positioning means to locate the film over said windows,

a plurality of continuous annular resilient gaskets thick relative to the film and resiliently compressible thereagainst, said gaskets having window openings corresponding to said windows in said base plate and fitting within said shoulder means and arranged to press said film members into position across said windows,

said positioning means and said locating means locating. each said film member on its respective shoulder means, and

means for compressing said gasket means against said film member to retain said film member in a planar condition against said base plate.

3. A character matrix array for a flying spot photographic character scanner having a thin film member on which at least one array of master characters is formed and positioning means formed on said film member, comprising a rigid base plate having one window formed therethrough for each array,

said film positioning means including at least one hole in said film member,

said base plate also having locating means including at least one corresponding pin for engaging with said positioning means and for reception in said film hole to locate the film precisely over said windows,

continuous annular resilient gasket means thick relative to the film and resiliently compressible thereagainst, said gasket means having window openings corresponding to said windows in said base plate,

and means for compressing said gasket means against said film member to retain said film member in a planar condition against said base plate. 

1. A character matrix array for a flying spot photographic character scanner having a thin film member on which master characters are formed and positioning means formed on said film member, comprising: a rigid base plate having windows formed therethrough, a peripheral shoulder formed on said plate surrounding the windows, said base plate also having locating means engaging with said positioning means to locate the film over said windows, said film member being a continuous piece fitting within said shoulder and having character arrays aligned with each of said windows, a resilient gasket member having a stiff backing and having window openings corresponding to and coincident with said windows in said base plate, and means for compressing said gasket means against said film member to retain said film member in a planar condition against said base plate.
 2. A character matrix array for a flying spot photographic character scanner having a plurality of separate thin film members on each of which at least one array of master characters is formed and positioning means formed on each said film member, comprising a rigid base plate having one window formed therethrough for each array, each film member fitting one each within each of said windows and having dimensions smaller than said windows, separate shoulder means formed around each of said windows, said base plate also having locating means engaging with said positioning means to locate the film over said windows, a plurality of conTinuous annular resilient gaskets thick relative to the film and resiliently compressible thereagainst, said gaskets having window openings corresponding to said windows in said base plate and fitting within said shoulder means and arranged to press said film members into position across said windows, said positioning means and said locating means locating each said film member on its respective shoulder means, and means for compressing said gasket means against said film member to retain said film member in a planar condition against said base plate.
 3. A character matrix array for a flying spot photographic character scanner having a thin film member on which at least one array of master characters is formed and positioning means formed on said film member, comprising a rigid base plate having one window formed therethrough for each array, said film positioning means including at least one hole in said film member, said base plate also having locating means including at least one corresponding pin for engaging with said positioning means and for reception in said film hole to locate the film precisely over said windows, continuous annular resilient gasket means thick relative to the film and resiliently compressible thereagainst, said gasket means having window openings corresponding to said windows in said base plate, and means for compressing said gasket means against said film member to retain said film member in a planar condition against said base plate. 